The Sacramento-based band releases ‘Diamond Eyes’ on Tuesday, its first record without bassist Chi Cheng, who remains semiconscious after a 2008 auto accident.

Hard rock thrives on conflict and chaos, and no band has found more beauty and soaring aggression within those ingredients than Deftones.

The Sacramento group has operated like this for years, a functioning dysfunctional group of musicians who nearly broke apart (again) during the struggle and combat of their last album, 2006's "Saturday Night Wrist," which nonetheless ended up as another stirring fusion of atmosphere and grinding guitar.

After the band finished recording, bassist Chi Cheng said at the time: "It's a really onerous, painful process … but it seems that kind of tension does make great music for us."

Four years later, band members convened for a final day of rehearsals in North Hollywood before leaving on a tour that began in Mexico City last weekend. They recently completed a new album, "Diamond Eyes," set for release on Tuesday. But Deftones did so without Cheng, 39, who now lies in a semiconscious state following a 2008 car accident in Santa Clara.

"His situation is present at all times," said guitarist Stephen Carpenter, bearded and burly in black, his corner of the rehearsal room filled with guitars, his 15 effects pedals and a laptop. "We're moving on with what we're doing, but we can never stop thinking about him."

The bassist remains unable to speak, but the shock of his accident and brain injury has contributed to a new state of mind for the platinum-selling rock band he helped establish with Carpenter, singer Chino Moreno, drummer Abe Cunningham and keyboardist/DJ Frank Delgado. There is a new sense of brotherhood and purpose beneath the Deftones banner.

On this afternoon, Moreno was noticeably healthy and trim. He first met Cheng as a teenager, and moved into his apartment after the singer's parents divorced. At the time, he said, Cheng was like a "big brother."

"One of our members was taken down," Moreno said of the crisis, and the band's reaction to it. "The little things that were getting in the way of us being friends and having fun seemed minuscule compared to what just happened to us.

"We didn't sit around and talk so much about it. Everybody gravitated towards their instruments and started playing."

Stepping into Cheng's role was Sergio Vega, formerly of the band Quicksand, who met the Deftones players during the first Warped Tour in 1995. Vega filled in once before, in 1999, when Cheng was sidelined by a staph infection. And he'll be with Deftones this fall on the band's tour with Alice in Chains and Mastodon (with an L.A. date yet to be announced).

At the time of Cheng's accident, the band was nearly done with an album that was to be called "Eros" and released in 2009. It was only a few vocals away from completion, but work stopped immediately. The band also began to express doubts about the album, and Moreno met with Nick Raskulinecz, producer of the Foo Fighters, Rush and Alice in Chains.

A fan of the band's hard-charging first two albums, the producer found "Eros" more ethereal than rocking, and less to his liking. "I knew what I wanted to hear and I didn't hear any of that in the record he was playing for me," Raskulinecz said. "I don't think it was a bad record, but it just wasn't the right record."

The band agreed, and made plans to record a new album with the producer, even if shelving an entire album after months of work and many thousands of dollars spent was a major decision. Moreno calls it "a gamble," particularly since the band had been mostly inactive as a live act.

Carpenter disagrees, saying the decision was easy. "I didn't think it was a gamble at all," says the guitarist. "I never have lack of confidence when it comes to making music.... We're not sending rockets into space to orbit Pluto."

Working with Raskulinecz also meant a shift in habits. In recent years, Deftones typically entered a studio with very little material already written and depended on inspiration, creating as they went. It's an expensive way to work, but after already shelving one album, Deftones didn't have that luxury.

Before entering the Pass studio in Hollywood, Deftones and Raskulinecz worked out the new songs and rehearsed them every day. "We were able to play the record in its entirety even before we put it to tape," Delgado said.

"Diamond Eyes" opens with a grinding, crushing riff, as the soaring voice of Moreno sings of escape on the title song through waves of beauty and desperation.

"More than anything, I tried to use the music to escape what was going on," said Moreno. "There's a lot of sex and violence in it, happiness, sadness. I figured people are going to expect a sad record, a dark record, a pity record, given the circumstances we've been through. If anything, that's what I wanted to stray from. I didn't want to come off sounding like a victim."

His favorite song of the moment is "Sex Tape," which offers a respite from the harsher side of Carpenter's guitars, with a dreamy, hopeful vocal floating amid waves of lush, heavy sound: "Cruising through the city after hours with me, fusing all our powers, here's to all our dreams."

"Thoughts of Chi were with us in the studio every day," Raskulinecz said of the fallen bassist. "But it was positive. It wasn't a bum-out, it wasn't a drag. It was like, ‘Dude, Chi would love this if he was here right now!' ‘Dude, he'd be stoked if he could hear this right now!' He was with us the whole time."

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